Most guys know how big their dick is. I’m willing to bet that nearly every dude out there has measured his erect penis at least once, especially as a teenager. And why not? We’re taught to rank all sorts of things, from athletic performance to academic performance to chest size (female and male), so why not cock size?

In some ways, cock size is the ultimate measure of masculinity. Saying a guy is “hung like a horse” or “small as a worm” usually produces the desired response. And why shouldn’t guys be concerned? Having a penis is one of the most basic definitions of what it means to be a man, after all. Until the advent of genetic and hormonal testing, it was pretty much the only biologically based definition of what it meant to be male. (We can discuss eunuchs at a different time.)

For some guys—especially younger guys–the connection between the size of their cock and their manhood is fairly direct. Having a bigger cock means a guy is more macho. Using that cock with lots of different partners can make him “The Man.”

For guys with little sexual experience, there’s an assumption that “bigger is better.” That’s not true and this might be one place where average is more advantageous. During sex, a guy with a larger than average dick probably doesn’t want to be “hanging in the breeze” and his partner may not want him trying to go “all in.” On the other hand, a guy with a small penis may have self-esteem issues and, in some cases, may have difficulty satisfying his partner through penetrative sex.

I think the focus on penis size—as well as number of partners—is primarily an issue for guys in their teens and twenties. As guys move through their 20s and into their 30s, most of them stop comparing their sex lives to other guys and try to focus on what makes them happy. For the vast majority of guys—even teens and twenty-somethings—that’s sex with a relational partner.

Dudes want to know how they compare to other guys, but friends don’t let friends see their erections. Especially straight dudes. Information about normal height and weight are readily available, but not for penis size. Although phys ed classes are good for telling a guy how fast (or slow) he is, erection competitions are not allowed.

Enter porn. It’s the easiest way to see someone else’s penis. Even if we all know those cocks aren’t exactly normal in size, a guy who wants to know will start using them as the basis for comparison. There are two reasons for that. The first is that porn provides the only source of information. The second is that porn sets a (the?) standard for what is a desirable penis, in much the same way that magazines like Cosmo and Vogue set a (the?) standard for what is a desirable woman’s body.

In real life, penises are almost always hidden. Nor can a dude “accidentally” end up naked with a stiffy in front of his buddies. As sociologist C. J. Pascoe details in “Dude, You’re a Fag,” straight teenage boys don’t want anyone to think they might possibly be gay. Despite the fact that teens are among the most accepting of gay rights, heterosexual teenage boys know that being called gay is a bad thing. That’s part of the reason why a guy needs to say “no homo” when asking his buddy to check out his well-cut biceps, chest or abs.

The only option is the surreptitious look in the locker room. But that produces another problem: those quick peeks give a guy a side view, but he typically sees his own Johnson top-down and thus foreshortened. He’s almost always going to come up short.

A recently published study by Debby Herbenick and her research team at the University of Indiana’s Center for Sexual Health Promotion gives us the details. The information on penis size is part of a series of studies designed to understand why some guys don’t use condoms regularly; guys who never use condoms, as well as guys who have latex allergies, weren’t included in the study.

The Findings

The average penis is about 14.15 cm (5.5 inches), measured on the underside of an erect penis from where the balls attach to the end. The most common size, or mode, is 14 cm (5.6 inches). About 75% of guys reported their Willy was between 12 and 17 cm long. The full range of scores is illustrated in the figure above, which I generated from the data provided by the authors. The scores are not normally distributed, which means that the figure is not symmetric and—for the mathematically able—the standard deviation (2.66 cm) does not provide an accurate percentile rank.

The study also revealed that a guy’s length doesn’t change based on whether he got hard using his imagination, his hand, or with a partner’s help. However, thickness does change; guys who measured themselves mid-blow job were notably thicker than anyone else.

How did they measure that?

The research team asked about 1,800 guys to take their measurements, and 1,661 answered the call. In return for their info, dudes who participated in the study received condoms that were custom-made to their specs. Custom-sized condoms! Who knew they even existed?

Because the guys were getting customized condoms, the research team believes there was little to no exaggeration about penis size. As they point out, their average was a little lower than prior studies that relied on self-reported penis size with less stringent safeguards, and a little higher than other studies that involved medical personnel with gloves, calipers, and rulers. (Think the stethoscope is always cold?)

The Research Project

Because size and comfort are big reasons for inconsistent condom use, this study provided guys with custom-fitted condoms and asked them to rate those condoms in comparison to standard sized condoms; all condoms were the same thickness, lubricated (in package), and came with no other information. The final analysis is based on nearly 6,000 experiences of vaginal or anal sex.

The results indicated that condom failure was less than 2% for both standard and custom-sized condoms. Overall, the men in the study said the custom condoms were more comfortable and they felt more confident about those rubbers. Guys with longer penises (16 cm or longer) reported notably lower failure rates with custom-sized condoms. They also said custom condoms were more comfortable and were (theoretically) willing to recommend them to friends.

I’m willing to bet that relationship quality is more important than how a guy’s cock compares to someone else’s. If you’re a guy and you’re reading this, you’ve probably figured out where you rank. Do you feel any different now that you know?

Ultimately, most guys realize that their cocksmanship is only relevant for themselves and their partner(s), and that what other people think doesn’t really matter when they’re getting it on. Most guys say they genuinely want to please their partner sexually, regardless of whether that’s a one-time partner, someone they’re dating, or someone they’ve married. Isn’t that pleasure more important than how a guy compares to other guys?